ABSTRACT
The facilitating effect of nifedipine on isoproterenol induced airway smooth muscle relaxation was studied in guinea pig tracheas. For isometric force measurement, 4 mm tracheal cylinders were suspended in incubation chambers in oxygenated physiologic medium. After 90 minutes of equilibration under 2 grams resting tension, at a temperature of 37 degrees C and pH of 7.4, concentration response curves for isoproterenol were performed with and without the addition of a 1 X 10(-5)M nifedipine dose. The experiments were then repeated using tissues precontracted with histamine. Our data show that in the nifedipine pretreated tissues, the EC50 of isoproterenol is shifted to the left (p less than 0.05) probably due to further reduction in cytosolic calcium by nifedipine. Our findings suggest that nifedipine might have a role in the treatment of asthma and obstructive airway disease.
Subject(s)
Isoproterenol/pharmacology , Muscle Contraction/drug effects , Muscle Relaxation/drug effects , Muscle, Smooth/physiology , Nifedipine/pharmacology , Animals , Drug Synergism , Guinea Pigs , In Vitro Techniques , Kinetics , Male , Muscle, Smooth/drug effects , Trachea/drug effects , Trachea/physiologyABSTRACT
This study was undertaken to examine the influence of carbon dioxide induced pH changes on the sensitivity of guinea pig airway smooth muscle to isoproterenol. The data indicate that alkalotic changes in media pH (pH 7.6 and 7.8) caused a significant decrease in the sensitivity of the airway to the beta-agonist when the tissue was at basal tone. When precontracted with histamine, however, acidosis (pH 7.0 and 7.2) enhanced, and alkalosis (pH 7.8) diminished the sensitivity of the smooth muscle to isoproterenol.
Subject(s)
Acid-Base Imbalance/physiopathology , Carbon Dioxide/pharmacology , Isoproterenol/pharmacology , Trachea/drug effects , Animals , Calcium/blood , Guinea Pigs , Hydrogen-Ion Concentration , In Vitro Techniques , MaleABSTRACT
The effect of CO2 induced pH changes on the response of airway smooth muscle to theophylline was studied. Our data show that simulated respiratory acid-base disturbances (pH range 7.0 to 7.8) have no significant effect on the response of isolated guinea pig tracheal cylinders at basal tone to theophylline. On the other hand, tracheal cylinders precontracted with histamine showed a diminished sensitivity to theophylline at pH values above 7.40, and an enhanced sensitivity at pH values below 7.40.
Subject(s)
Carbon Dioxide/pharmacology , Theophylline/pharmacology , Trachea/drug effects , Animals , Guinea Pigs , Histamine/pharmacology , Hydrogen-Ion Concentration , In Vitro Techniques , Male , Muscle Contraction/drug effects , Muscle, Smooth/drug effectsABSTRACT
Sleep apnea occurring in association with neurologic lesions is usually of the central type. We have described a patient in whom obstructive sleep apnea followed a lateral medullary syndrome. We hypothesize that the upper airway obstruction during sleep was due to weakness of the palatal and pharyngeal muscles resulting from the neurologic lesion. The patient initially had reduced respiratory center motor output (mouth occlusion pressure) which increased significantly after tracheostomy. We conclude that obstructive as well as central apnea may follow neurologic lesions. Each patient should be carefully evaluated to provide proper treatment.
Subject(s)
Intracranial Embolism and Thrombosis/complications , Lateral Medullary Syndrome/complications , Sleep Apnea Syndromes/etiology , Humans , Lateral Medullary Syndrome/physiopathology , Male , Middle Aged , Respiration Disorders/etiology , Respiratory Center/physiopathology , Sleep Apnea Syndromes/surgery , TracheotomyABSTRACT
A diagnosis of systemic lupus erythematosus (SLE) was established in a 54-year-old woman with a compatible history, as well as patchy alopecia, anemia, arthralgias, and a positive LE cell preparation. Sixteen months later bilateral hilar and mediastinal lymph nodes appeared on chest roentgenogram. Sarcoidosis was diagnosed when hypercalcemia and noninfectious, noncaseating epithelioid granulomas were found in the skin and liver. The sarcoidosis remitted with corticosteroid therapy, but slowly advancing renal failure ultimately resulted in the patient's death. We believe the concurrence of SLE and sarcoidosis had not been previously reported in the English literature. Immune mechanisms are discussed.
Subject(s)
Lupus Erythematosus, Systemic/complications , Sarcoidosis/complications , Female , Humans , Lupus Erythematosus, Systemic/immunology , Male , Middle Aged , Sarcoidosis/immunologyABSTRACT
Twenty-six patients undergoing transnasal fiberoptic bronchoscopy (FOB) were electrocardiographically monitored for 12 hours before, during, and 12 hours after bronchoscopy. We measured arterial lidocaine concentrations during the procedure as well as arterial blood gases before and after the procedure. The incidence of total arrhythmias, including sinus tachycardia, during the control period was 69 percent; minor arrhythmias, 69 percent; and major arrhythmias, 8 percent. During FOB, the incidence of total and minor arrhythmias increased to 77 and 73 percent, respectively; however, the incidence of major arrhythmias decreased to 4 percent. Arterial lidocaine concentrations ranged widely, from 0.1 to 8.7 microgram per milliliter with a mean peak level of 5.0 +/- 0.6 microgram per milliliter, which was reached between 5 and 30 minutes after the insertion of the bronchoscope. We conclude that the incidence of cardiac arrhythmias, excluding sinus tachycardia, during FOB is low and that lidocaine anesthesia probably exerts a protective effect against the development of major arrhythmias during the procedure.
